Snowmobiles are well known as vehicles particularly well suited for travel over terrain covered by snow and ice. Typically, a snowmobile is propelled by a motor-driven endless belt, and guided directionally by a pair of steerable forwardly mounted skis. The skis are connected to a steering column through a steering linkage. The operator, by manipulating handlebars attached to the top of the steering column, determines the position of the skis to steer the snowmobile.
For maximum operator convenience and safety, it is desirable that the handlebars and steering column be adjustable over a range of heights with respect to the passenger seat in the snowmobile. One known method of providing such adjustment is to provide a steering column in two sections, pivotally mounted relative to each other at a lateral pivot axis along the steering column. A clamp, secured by bolts, maintains the two column sections substantially rigid with respect to each other after adjustment.
One disadvantage of this pivotal mounting, however, is that a pivot near the steering column base results in a substantial rearward displacement of the handlebars in order to lower them. On the other hand, if the pivot point is raised in order to reduce the horizontal component of the pivotal motion, the handlebars undergo substantial rotation about a horizontal axis as they are adjusted upward or downward. Consequently the handlebars are moved out of the desired orientation, in which gauges and controls mounted on the handlebars are optimally positioned for reading and handling. Yet another problem with this arrangement is the inconvenience of re-adjusting the steering column position. The bolts must be loosened, the adjustment made, and the bolts re-tightened.
The prior art, particularly in connection with bicycle handlebars, evidence attempts to enhance operation by adjustable handlebars. U.S. Pat. No. 689,217 to Palmer granted Dec. 17, 1981 shows bicycle handlebars 17 mounted to a stem 11 held by a clamp 10. Loosening of clamp 10 permits sliding of the stem and 180.degree. rotation of it. U.S. Pat. No. 4,023,436 to Dodge granted May 17, 1977 shows in FIG. 31 a bicycle handle having at least three sections and two pivots. Bolts are loosened to permit the sections of the handlebar to pivot with respect to one another. U.S. Pat. No. 1,595,557 to Mamiya granted Aug. 10, 1926 discloses a folding bicycle handle in which separate handle sections are mounted to pivot relative to one another, but normally held against such pivoting by a spring 25 which urges pawls 24 against a toothed member 16.
While these prior art approaches provide some satisfaction, particularly in connection with bicycle handles, they fail to meet the need for a means for rapidly and conveniently adjusting a steering column, yet ruggedly and securely maintaining the column in its selected adjustment position, and further permitting vertical handlebar adjustment without undue horizontal movement or rotation of the handlebars out of their desired angular position.
Therefore, it is an object of the present invention to provide a means for adjusting handlebars to suit a variety of operators.
Another object of the invention is to provide a means for rapidly and conveniently changing the handlebar adjustment.
Another object is to provide for adjusting the height of handlebars, without undue forward or rearward movement of the handlebars, and without rotation of the handlebars out of their desired orientation.
Yet another object of the invention is to provide a means for securely maintaining the handlebar in its desired, adjusted position, thereby to provide a rugged, long-lasting structure.